The present invention relates to optical transceiver modules. More specifically, the invention relates to optical transceiver modules with multiple channels including a dual row pattern of optical emitters/detectors and separate transmit and detect electronics.
As fiber optics developed, many new technologies emerged to enhance their use. For example, fairly recently, a specification for a new generation of optical modular transceivers was developed named “small form-factor pluggable” (SFP). SFP transceivers are designed to be high bandwidth, small physical size and easily changeable (including being hot-swappable) on the line card of the network device.
Unfortunately, integrated circuit (e.g., application specific integrated circuit or ASIC) densities have increased to the point that line cards are now optical port density limited, rather than switch or processor limited. Thus, the electronics on the motherboards of the line card have the capacity to process more optical information than is being transmitted and received from the optical ports of the line card. This extra capacity is potential bandwidth that is not being realized. As a result, many line cards that use conventional SFP optics strand bandwidth.
There have been many attempts to achieve higher optical port densities. For example, parallel ferrule connectors have been utilized to solve the problem of optical port density on the line card faceplate. However, this typically requires fanout cables that are bulky, expensive and may be unreliable.
Single-mode parallel solutions are available, but they have typically been very large, expensive and difficult to manufacture. Additionally, they may require permanently attached fiber pigtails due to alignment requirements.
As a solution to solve the high cost of these early parallel offerings, the parallel vertical cavity self emitting laser (VCSEL) technology was developed. However, VCSEL technology blossomed at shorter wavelengths (e.g., 850 nm) and enabled only very short multi-mode applications. Also, the majority of VCSEL based parallel optics are designed for parallel data transfer, where all channels of data are synchronous or plesiochronous. These products, therefore, typically do not allow multiple channels that are totally independent (e.g., four independent, serial data channels). Lastly, the reliability of this solution is still questionable.
It would be beneficial to have innovative techniques for providing optical transceiver modules that provides multiple channel optics without the disadvantages normally associated with this capability. Additionally, it would be beneficial if the optical and electrical crosstalk is reduced or eliminated.